Indicia reading terminal having multiple setting imaging lens

ABSTRACT

An indicia reading terminal can include a multiple setting imaging lens assembly and an image sensor having an image sensor array. In one embodiment, an indicia reading terminal in an active reading state can cycle through a set of different lens settings, expose pixels of an image sensor array during an exposure period when each new lens setting is achieved, and attempt to decode decodable indicia represented in frames of image data captured corresponding to each exposure period. In one embodiment, movement of an imaging lens assembly lens element can be provided with use of a hollow stepper motor.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/132,480, filed Jun. 3, 2008 entitled “Indicia Reading Terminal HavingMultiple Setting Imaging Lens,” which claims priority under 35 U.S.C.§119(e) to Provisional Patent Application No. 60/933,022, entitled“Indicia Reading Terminal Processing Plurality of Frames of Image DataResponsively To Trigger Signal Activation” filed Jun. 4, 2007.Application Ser. No. 12/132,480 is related to U.S. patent applicationSer. No. 12/132,462, filed Jun. 3, 2008 entitled “Indicia ReadingTerminal Processing Plurality of Frames Of Image Data Responsively toTrigger Signal Activation.” Each of the above applications isincorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The invention relates to an indicia reading terminal in general, andspecifically, to an indicia reading terminal having a multiple settingimaging lens assembly.

BACKGROUND OF THE PRIOR ART

A majority of commercially available image based indicia readingterminals are equipped with fixed position (single setting) imaging lensassemblies. Advances in lens technology, illumination technology, imagesensor technology, and image processing technology have increased thedepth of field of such terminals. However, the operational field of viewof such terminals is limited by the single setting aspect of the lensassemblies of such terminals.

BRIEF DESCRIPTION OF THE DRAWINGS

The features described herein can be better understood with reference tothe drawings described below. The drawings are not necessarily to scale,emphasis instead generally being placed upon illustrating the principlesof the invention. In the drawings, like numerals are used to indicatelike parts throughout the various views.

FIG. 1 is a schematic diagram illustrating an indicia reading terminalhaving a multiple setting imaging lens assembly, wherein the imaginglens assembly has a plurality of lens elements, and wherein the imaginglens assembly is set to a first setting.

FIG. 2 is a schematic diagram illustrating an indicia reading terminalhaving a multiple setting imaging lens assembly, wherein the imaginglens assembly has a plurality of lens elements, and wherein the imaginglens assembly is set to a second setting.

FIG. 3 is a schematic diagram illustrating an indicia reading terminalhaving a multiple setting imaging lens assembly, wherein the imaginglens assembly has a plurality of lens elements, and wherein the imaginglens assembly is set to a third setting.

FIG. 4 is an exemplary block diagram illustrating an exemplary componentof an indicia reading terminal in one embodiment.

FIG. 5 is an exploded perspective assembly view of an imaging module inone embodiment.

FIG. 6 is a perspective view of an assembled imaging module in oneembodiment.

FIG. 7 is a timing diagram illustrating operation of an indicia readingterminal in one embodiment.

FIG. 8 is a cutaway side view of a lens movement assembly in oneembodiment.

FIG. 9 is a perspective view of a hollow stepper motor in oneembodiment.

FIG. 10 is a cutaway side view illustrating a non-zooming imaging lensassembly which can be incorporated in an indicia reading terminal.

FIG. 11 is a cutaway side view illustrating another non-zooming imaginglens assembly which can be incorporated in an indicia reading terminal.

FIG. 12 is a cutaway side view illustrating a zooming imaging lensassembly which can be incorporated in an indicia reading terminal.

FIG. 13 is a perspective view of an indicia reading terminalincorporating a hand held housing in one embodiment.

FIG. 14 is a cutaway side view of an indicia reading terminal as shownin FIG. 13.

DETAILED DESCRIPTION OF THE INVENTION

There is provided an indicia reading terminal having a multiple settingimaging lens assembly (imaging lens). As shown in FIGS. 1, 2, and 3,terminal 10 can have an image sensor 32 and an imaging lens assembly 40(imaging lens) capable of multiple lens settings. A multiple settingimaging lens assembly can be provided e.g., with use of one or more lenselements capable of being moved into different multiple positions, withuse of one or more lens elements having adjustable lens surfacecurvatures, with use of one or more lens elements having an adjustableindex of refraction, or with use of any combination of the above. In theparticular embodiment of FIGS. 1, 2, and 3, a multiple lens settingindicia reading terminal comprises one or more multiple position lenselements. In the specific embodiment of FIGS. 1, 2, and 3, imaging lensassembly 40 comprises seven lens elements; namely, elements 402, 403,404, 406, 407, 408, 410 where the combination of elements 403 and 404and the combination of lens elements 407 and 408 are lens doublets. Inthe embodiment of FIGS. 1, 2, and 3, imaging lens assembly 40 focuses animage of a decodable indicia disposed on a target substrate 50 onto anactive surface of image sensor 32. In one embodiment, an active surfaceof an image sensor can be provided by an image sensor pixel array 33(image sensor array).

A well-corrected lens assembly can be treated as a “black box” whosecharacteristics are defined by its cardinal points; namely, its firstand second focal points, its first and second principal points, and itsfirst and second nodal points. The first focal point is the point atwhich light rays (for example, coming from the left) from an infinitelydistant object and parallel to the optical axis are brought to a commonfocus on the optical axis. If the rays entering the lens assembly andthose emerging from the lens assembly are extended until they intersect,the points of intersection will define a surface, usually referred to asthe principal plane. The intersection of this surface with the opticalaxis is the principal point. The “second” focal point and the “second”principal plane are those defined by rays approaching the system fromthe right. The “first” points are those defined by rays from the left.

The focal length of a lens assembly (also referred to as the effectivefocal length, EFL) is the distance from the principal point to the focalpoint. The back focal length (BFL) or the back focus is the distancefrom the vertex of the last surface of the system to the second focalpoint (again for light traveling through the lens assembly from left toright). The front focal length (FFL) is the distance from the frontsurface to the first focal point. The nodal points are two axial pointssuch that a ray directed at the first nodal point appears (after passingthrough the system) to emerge from the second nodal point parallel toits original direction. When a lens assembly is bounded on both sides byair (as is true in the great majority of applications), the nodal pointscoincide with the principal points.

FIGS. 1, 2 and 3 all show the respective effective focal points, nodalpoints, and field angles in both image and object space. Note that sincethe lens assembly is bounded on both sides by air, the nodal pointscoincide with the principal points. The field of view half angle isdefined by the ray which originates at the most extreme field point ofobject 50 that projects to the point farthest removed from the opticalaxis of image sensor 32. The focal point, nodal point and field of viewangles in object space are noted as f_(n), n_(n) and θ_(n) and thecorresponding points in object space are noted as f_(n)′, n_(n)′, andθ_(n)′. The subscript “n” represents the example associated with FIGS.1, 2, and 3 respectively.

In general, using paraxial approximations, the distance from the lensobject space nodal point to the object P_(n), the distance from theimage space nodal point to the image Q_(n), and the focal length f_(n)are related through the lens equation:1/f _(n)=1/P _(n)+1/Q _(n)  eq. 1

As the lens equation demonstrates, when the focal length is constant,the plane of nominal focus for the lens assembly can be changed simplyby changing the separation between the object and the lens principalplane. If the focal length and image distance are similar in value,which is often the case in bar code imaging systems, then the imagedistance change will be minimal for a major shift in the object plane.The field of view for such lens assembly is determined by the size ofthe active surface of the image sensor. Similarly using paraxialapproximations, the field angles for image space and object space areidentical, thus:θ′_(n)=θ_(n)

Referring again to FIGS. 1, 2, and 3, the half field of view angleθ′_(n) is related to the optical configuration:Tan(θ′_(n))=X _(n) /Q _(n)  eq. 2

This can be substituted into the lens equation to eliminate Q_(n) andgiving:Tan(θ_(n))=X _(n)*(1/f _(n)−1/P _(n))  eq. 3

From this expression we can observe that the field of view for a lensassembly will not change strongly with object distance P_(n) as long asthe object distance is significantly larger than the lens focal lengthf_(n). In bar code/indicia reading systems, this condition is usuallysatisfied. Conversely, if one wants to change the field of view, thiscan be most effectively done by changing the focal length f_(n). Ingeneral, one can assert that if the lens curvatures, materialsdimensions, and lens separations relative to each are unchanged, thenthe focal length of the lens assembly will be unchanged. Similarly, thefocal length can be changed by varying any of these attributes eithersingularly or more likely together.

Where a focal length of an imaging lens assembly remains constant, abest focus distance of terminal 10 (the distance between the terminaland a substrate at which the terminal is optimally focused) can beadjusted by changing the distance between a focal point of imaging lensassembly 40 and the image plane, i.e., image sensor array 33 (the activesurface of image sensor 32). A focal length of imaging lens assembly 40can be maintained at a constant value by maintaining the relativepositions of lens elements 402, 403, 404, 406, 407, 408, 410. A field ofview (FOV) angle of an imaging lens assembly 40 is a function of animaging lens assembly's focal length (the FOV angle of a lens istypically expressed in terms of “half FOV” units) and image planedistance. Where image plane distances are significantly larger than animaging lens assembly's focal length, an FOV angle of imaging lensassembly 40 can be maintained at a substantially constant value byretaining the relative positions between lens elements. A focal lengthof an imaging lens assembly 40 can be changed by adjusting a relativeposition between lens elements of an imaging lens assembly havingmultiple lens elements. Thus, changing a relative position between lensgrouping 420 and grouping 430 changes a focal length of imaging lensassembly 40. As mentioned, an FOV angle of imaging lens assembly 40 is afunction of the imaging lens assembly's focal length. Accordingly, anFOV angle of imaging lens assembly 40 will change as grouping 420 ismoved relative to grouping 430 or vice versa. Because the distancebetween a focal point position and image sensor 32 (the image plane)will also change as one grouping is moved relative to another, a changein the relative position between grouping 420 and grouping 430 can beexpected to produce a change in a best focus position of terminal 10 aswell as a change in the focal length and field of view angle. The act ofreducing a field of view angle of a lens while increasing a best focusdistance is often referred to as “zooming” Where an imaging lensassembly is capable of zooming, it is often referred to as a “zoomlens.”

In one embodiment, terminal 10 is configured so that a setting ofimaging lens assembly 40 can be switched between a plurality of lenssettings. In one embodiment, the plurality of lens settings is threelens settings.

Various lens settings of imaging lens assembly 40, in one embodiment,are illustrated with reference to FIGS. 1, 2, and 3. In setting (a), ashort range setting, terminal 10 has a best focus distance of 2″ and ahalf FOV angle of 35°. With lens 40 set to setting (b), a medium(intermediate) range setting, terminal 10 has a best focus distance of7″ and a half FOV angle of 36.9°. With lens 40 set to setting (c), along range setting, terminal 10 has a best focus distance of 24″ and ahalf FOV angle of 11.5°. A focal length of imaging lens assembly 40 canbe unchanged relative to setting (a) and setting (b). Between setting(a) and setting (b), a focal length of lens assembly 40 can bemaintained at a constant value by maintaining a constant spacing betweenlens elements. Between setting (a) and setting (b) in a specificembodiment, a focal length of lens assembly 40 can be maintained at aconstant value by maintaining a constant spacing between lens groupingswhere the groupings are moved farther from an image sensor array betweensetting (a) and setting (b). By maintaining focal length at a constantvalue the FOV angle of lens assembly 40 will not change substantiallyprovided the image plane distance is significantly larger than the lensfocal length. Distance and angular measurements herein are given asapproximate measurements. A summary of possible lens settings in oneembodiment is summarized in Table 1.

TABLE 1 Focal Half FOV Range Lens Setting Length Angle Best FocusDistance Short (a) 4.7 mm 35° 2″ Intermediate (b) 4.7 mm 36.9° 7″ Long(c) 17.3 mm  11.5° 24″

Regarding lens setting (c), it is advantageous for terminal 10 to have areduced FOV angle at a long range setting so that a resolution of imagedata representing a target indicia is improved. Terminal 10 can beadapted so that when terminal 10 operates to capture frames of imagedata for subjecting to decoding, terminal 10 cycles between three lenssettings. Terminal 10 can cycle between lens settings such that for acertain exposure period, the lens setting is at a first lens setting;for a subsequent exposure period, the lens setting is at a second lenssetting, and for a further subsequent exposure period, the lens settingis at a third lens setting, and continuing with the cycling so thatduring an exposure period after the further subsequent exposure period,the lens returns to a first or previous lens setting and so on. Framesthat are captured corresponding to and representing light incident on animage sensor array during the certain, subsequent, and furthersubsequent exposure periods can be subject to an indicia decodingattempt such as a bar code decoding attempt.

In an alternative embodiment as shown in Table 2, imaging lens assembly40 can have at least three lens settings. In each of the lens settingssummarized in Table 2, imaging lens assembly 40 has a different focallength, a different half FOV angle, and a different best focus distance.

TABLE 2 Focal Half FOV Range Lens Setting Length Angle Best FocusDistance Short (a) 4.7 mm 35° 2″ Intermediate (b) 8 mm 23.4° 7″ Long (c)17.3 mm 11.5° 24″

A multiple setting lens assembly for use with terminal 10 can beconveniently provided by employing a motor for moving lens elementsrelative to an image plane and/or relative to one another. It will beunderstood, however, that a multiple setting imaging lens can beprovided utilizing alternative technologies. For example, spring-basedactuators can be employed for moving lens elements to an image planeand/or each other. Also, fluid lens technologies can be employed. Fluidlens technologies can be employed for purposes of adjusting a curvatureof a lens assembly lens element. Fluid lens technologies can also beemployed in order to change an index of refraction of a lens assemblylens element by way of applying energy to the lens element to vary anoptical property of a liquid included in the lens element.

A block diagram of an electrical component circuit diagram supportingoperations of terminal 10 is shown in FIG. 4. Image sensor 32 can beprovided on an integrated circuit having an image sensor pixel array 33(image sensor array), column circuitry 34, row circuitry 35, a gainblock 36, an analog-to-digital converter 37, and a timing and controlblock 38. Image sensor array 33 can be a two dimensional image sensorarray having a plurality of light sensitive pixels formed in a pluralityof rows and columns. Terminal 10 can further include a processor 60, anillumination control circuit 62, a lens control circuit 64, an imaginglens assembly 40, a direct memory access (DMA) unit 70, a volatilesystem memory 80 (e.g., a RAM), a nonvolatile system memory 82 (e.g.,EPROM), a storage memory 84, a wireline input/output interface 90 (e.g.,Ethernet), and an RF transceiver interface 92 (e.g., IEEE 802.11).Regarding illumination control circuit 62, illumination control circuit62 can receive illumination control signals from processor 60 and canresponsively deliver power to one or more illumination light sourcessuch as light sources 604, and one or more aiming light sources such asaiming light source 610. Terminal 10 can also include a keyboard 94, atrigger button 95, and a pointer controller 96 for input of data and forinitiation of various controls and a display 97 for output ofinformation to an operator. Terminal 10 can also include a system bus 98providing communication between processor 60 and various components ofterminal 10. DMA unit 70 can be provided by, e.g., a field programmablegate array (FPGA) or an application specific integrated circuit (ASIC).While shown as being separate units, DMA unit 70 and processor 60 can beprovided on a common integrated circuit. In a further aspect, terminal10 can include multiple image sensors and can include a plurality oflight source banks. The light source banks can be controlled accordingto various control methods that can vary depending on which of aplurality of available operating configurations are active. An exampleof terminals that can include a plurality of image sensors and which caninclude plural light source banks that can be controlled in accordancewith a variety of different settings depending on which of a pluralityof different candidate configurations is active are described in U.S.patent application Ser. No. 12/132,462 entitled, “Indicia ReadingTerminal Processing Plurality of Frames of Image Data Responsively ToTrigger Signal Activation,” filed concurrently herewith and incorporatedherein by reference.

In response to control signals received from processor 60, timing andcontrol circuit 38 can send image sensor array timing signals to array33 such as reset, exposure control, and readout timing signals. After anexposure period, a frame of image data can be read out. Analog imagesignals that are read out of array 33 can be amplified by gain block 36converted into digital form by analog-to-digital converter 37 and sentto DMA unit 70. DMA unit 70, in turn, can transfer digitized image datainto volatile memory 80. Processor 60 can address frames of image dataretained in volatile memory 80 for decoding of decodable indiciarepresented therein.

Referring to FIGS. 5 and 6, an imaging module for supporting variouscomponents of terminal 10 is described. Mounted on first circuit board602 can be image sensor 32, illumination light sources 604 (e.g., LEDs),and aiming light source 610 which can be provided by a laser diodeassembly. A shroud 612 can be disposed forwardly of image sensor 32, anddisposed forwardly of shroud 612 can be a lens moving assembly 302,which in the embodiment of FIG. 5 can be provided by a hollow steppermotor assembly having more than one hollow stepper motor. An opticalplate 618 having diffusers 620 for diffusing light from illuminationlight sources 604 can be disposed over lens moving assembly 302 so thathole 622 fits over outer barrel 304 as will be described in greaterdetail herein. An imaging module in an assembled form is shown in FIG.6.

A timing diagram further illustrating operation of terminal 10, in oneembodiment, is shown in FIG. 7. Timeline 202 shows a state of a triggersignal which may be made active by depression of trigger button 95.Terminal 10 can also be adapted so that a trigger signal can be madeactive by the terminal sensing that an object has been moved into afield of view thereof or by receipt of a serial command from an externalcomputer. Terminal 10 can also be adapted so that a trigger signal ismade active by a power up of terminal 10. For example, in oneembodiment, terminal 10 can be supported on a scan stand and used forpresentation reading. In such an embodiment, terminal 10 can be adaptedso that a trigger signal represented by timeline 202 can be active forthe entire time terminal 10 is powered up. With further reference to thetiming diagram of FIG. 7, terminal 10 can be adapted so that after atrigger signal is made active at time 220, pixels of image sensor 32 areexposed during first exposure period EXP₁ occurring during a first timeperiod followed by second exposure period EXP₂ occurring during a secondtime period, third exposure period EXP₃ occurring during a third timeperiod and so on (after time 220 and prior to first exposure periodEXP₁, parameter determination frames subject to parameter determinationprocessing may be optionally captured subsequent to parameterdetermination exposure periods not indicated in FIG. 7). Referring tothe timing diagram of FIG. 7, terminal 10 may expose, capture andsubject to unsuccessful decode attempts N−1 frames of image data priorto successfully decoding a frame of image data corresponding to exposureperiod EXP_(N). An exposure control signal in one embodiment isrepresented by timeline 204 of FIG. 7.

Terminal 10 can be adapted so that after pixels of image sensor array 33are exposed during an exposure period, a readout control pulse isapplied to array 33 to read out analog voltages from image sensor 32representative of light incident on each pixel of a set of pixels ofarray 33 during the preceding exposure period. Timeline 206 illustratesa timing of readout control pulses applied to image sensor array 33. Areadout control pulse can be applied to image sensor array 33 after eachexposure period EXP₁, EXP₂, EXP₃, EXP_(N−1), EXP_(N). Readout controlpulse 232 can be applied for reading out a frame of image data exposedduring first exposure period EXP₁. Readout control pulse 234 can beapplied for reading out a first frame of image data exposed duringsecond exposure period EXP₂, and readout pulse 236 can be applied forreading out a frame of image data exposed during third exposure period,EXP₃. A readout control pulse 238 can be applied for reading out a frameof image data exposed during exposure period EXP_(N−1) and readoutcontrol pulse 240 can be applied for reading out a frame of image dataexposed during exposure period EXP_(N).

Terminal 10 can be adapted so that making active trigger signal 202drives terminal 10 into an active reading state. After analog voltagescorresponding to pixels of image sensor array 33 are read out anddigitized by analog-to-digital converter 37, digitized pixel valuescorresponding to the voltages can be received (captured) into systemvolatile memory 80. Terminal 10 can be adapted so that processor 60 cansubject to a decode attempt a frame of image data retained in memory 80.For example, in attempting to decode a 1D bar code symbol represented ina frame of image data, processor 60 can execute the following processes.First, processor 60 can launch a scan line in a frame of image data,e.g., at a center of a frame, or a coordinate location determined toinclude a decodable indicia representation. Next, processor 60 canperform a second derivative edge detection to detect edges. Aftercompleting edge detection, processor 60 can determine data indicatingwidths between edges. Processor 60 can then search for start/stopcharacter element sequences, and if found, derive element sequencecharacters character by character by comparing with a character settable. For certain symbologies, processor 60 can also perform a checksumcomputation. If processor 60 successfully determines all charactersbetween a start/stop character sequence and successfully calculates achecksum (if applicable), processor 60 can output a decoded message.When outputting a decoded message, processor 60 can one or more of (a)initiate transfer of the decoded message to an external device, (b)initiate display of a decoded message on a display of terminal 10, (c)attach a flag to a buffered decoded message determined by processor 60,and (d) write the decoded message to an address on long term memory,e.g., 82 and/or 84. At the time of outputting a decoded message,processor 60 can send a signal to an acoustic output device of terminal10 (not shown) to emit a beep.

Still referring to the timing diagram of FIG. 7, timeline 208 indicatesthe time at which processor 60 attempts to decode a first frame of imagedata corresponding to exposure period EXP₁ (i.e., the frame of imagedata having image data representing light incident on pixels of imagesensor array 33 during first exposure period EXP₁). It is seen thatprocessor 60 may commence attempting to decode using a first frame ofimage data a time after readout control pulse 232 to account for timedelay in image data being captured into memory 80. Referring to timeline210, timeline 210 indicates the time at which processor 60 attempts todecode a second frame of image data corresponding to and representinglight incident on image sensor array 33 during second exposure periodEXP₂. It is seen that processor 60 may commence attempting to decodeusing a second frame of image data a time after readout control pulse234 to account for time delay in image data being captured into memory80. Referring to timeline 212, timeline 212 indicates the time at whichprocessor 60 attempts to decode a third frame of image datacorresponding to and representing light incident on image sensor array33 during third exposure period EXP₃. It is seen that processor 60 maycommence attempting to decode using a third frame of image data a timeafter readout control pulse 236 to account for time delay in image databeing captured into memory 80. Referring to timeline 214, timeline 214indicates the time at which processor 60 attempts to decode an N−1^(th)frame of image data corresponding to exposure period EXP_(N−1). It isseen that processor 60 may commence attempting to decode using theN−1^(th) frame of image data a time after readout control pulse 238 toaccount for a time delay in image data being captured into memory 80.Referring to timeline 216, timeline 216 indicates the time at whichprocessor 60 attempts to decode an N^(th) frame of image datacorresponding to exposure period EXP_(N). It is seen that processor 60may commence attempting to decode using the N^(th) frame of image data atime after readout control pulse 240 to account for time delay in imagedata being captured into memory 80.

In one embodiment, imaging lens assembly 40 can comprise moving lenselements which can be in a static (non-moving) state during exposureperiods and in a moving state intermediate of exposure periods.Referring to timeline 218, timeline 218 indicates static period andmoving (in motion) periods of a lens. Terminal 10 can be adapted so thatduring exposure periods EXP₁, EXP₂, EXP₃, EXP_(N−1), and EXP_(N) lenselements are maintained in a static state and intermediate of exposureperiods EXP₁, EXP₂, EXP₃, EXP_(N−1), and EXP_(N) lens elements are inmotion. Terminal 10 can be adapted so that lens control circuit 64initiates control signals to move a lens element at about the time ofinitiation of readout control signal 232, 234, 236, 238, 240 and furtherso that lens elements responsively move in response to receipt of thetiming signals during motion periods 262, 264, 266, 268, 270 asindicated in timeline 218. In the example of the timing diagram of FIG.7, it is seen that processor 60 attempts to decode for bar code symbolsrepresented in a frame of image data during motion periods of imaginglens assembly 40. Terminal 10 can be adapted so that lens elements ofimaging lens assembly 40 are in motion while processor 60 attempts todecode a bar code symbol represented in a frame of image data.

Referring to FIGS. 8 and 9, a lens moving assembly 302 is described. Alens moving assembly 302 can comprise one or more hollow stepper motors.A hollow stepper motor, in one embodiment, generally is characterized bya permanent magnet equipped inner barrel, forming the rotor portion ofthe motor. A hollow stepper motor, in one embodiment, can further becharacterized by a coil equipped outer barrel, supporting the innerbarrel. Hollow stepper motors exhibit reduced size relative to othertypes of motors and allow for precision adjustment of lens elementpositions. In one embodiment an inner barrel portion of a hollow steppermotor can include threads that are threadably received in threads of anouter barrel. With such a thread arrangement, the motor can sustain highimpact relative to gear based motor arrangements. In one embodiment,threads for receiving an inner barrel in relation to an outer barrel caninclude threads complementarily configured so that an inner barrel ismaintained at a position with respect to outer barrel 304 by way offrictional forces and without application of external energy.Accordingly, a lens setting can be controlled to remain at a certainsetting simply by avoiding supplying current to a lens driver coil. Bycomparison, alternative lens moving assemblies, while desirable in someinstances, require applied power for maintaining a fixed lens setting.For example, motion systems including spring loaded lens movingmechanisms such as voice coil motors and helimorph piezo actuatorsrequire power for maintaining of a certain lens setting. Accordingly, amajor advantage of a hollow stepper motor, in one embodiment is reducedpower consumption. In the embodiment of FIGS. 8 and 9, lens movingassembly 302 comprises the lens elements of imaging lens assembly 40 asshown in the particular embodiment of FIGS. 1, 2, and 3, stationaryouter barrel 304, first inner barrel 306, and second inner barrel 308.In the embodiment of FIG. 8, imaging axis 30 extends perpendicularlythrough image sensor 32 and through a plane of each lens element.

Regarding outer barrel 304, outer barrel 304 can comprise a first set ofcoils 310 corresponding to first inner barrel 306 and a second set ofcoils 312 corresponding to second inner barrel 308. First set of coils310 includes first coil 314 and second coil 316. Second set of coils 312likewise can comprise first coil 318 and second coil 320. Thecombination of first inner barrel 306 and the first set of coils 310form a first hollow stepper motor while the combination of second innerbarrel 308 and a second set of coils 312 form a second hollow steppermotor.

Further regarding lens moving assembly 302, outer barrel 304 includesfirst teeth 350 for engaging teeth 351 of first inner barrel 306 andsecond teeth 352 for engaging teeth 353 of second inner barrel 308. Thecombination of teeth 350 and teeth 351 provide movement of first innerbarrel 306 along axis 30 when the first inner barrel 306 is caused torotate. The combination of teeth 352 and teeth 353 provide movement ofsecond inner barrel 308 along axis 30 when second inner barrel 308 iscaused to rotate.

Operation of an exemplary hollow stepper motor is further described withreference to FIG. 9. Each of first and second inner barrels 306 and 308can be provided as shown in FIG. 9. While the description of FIG. 9relates to inner barrel 306 and coil set 310, it is understood that thedescription is also applicable to the hollow stepper motor comprisingbarrel 308 and second coil set 312. Inner barrel 306 can have permanentmagnets 330 of alternating north and south polarity, which arealternately formed about the circumference of barrel 306. First coil 314can have alternating teeth 332, 334 defined by gap 336. When currentflows through coil 314 in a forward direction, magnetic fields ofopposite polarity are formed at successively adjacent teeth, e.g., teeth332, 334 of coil 314. When current flows through coil 314 in a backwarddirection, magnetic fields of opposite polarity are again formed atsuccessively adjacent teeth of coil 314, except the polarity of themagnetic field is the opposite of its polarity during forward directioncurrent flow. Similarly, second coil 316 can have alternating teeth 342,344 defined by gap 346. When current flows through coil 316 in a forwarddirection, magnetic fields of opposite polarity are formed atsuccessively adjacent teeth. When current flows through coil 316 in abackward direction, magnetic fields of opposite polarity are againformed at successively adjacent teeth of coil 316, except the polarityof the magnetic field is the opposite of its polarity during forwarddirection current flow.

For rotating inner barrel 306, current can be applied in forward andbackward direction in first and second coil 314, 316 in a timed sequencecoordinated manner to urge inner barrel 306 in a desired direction untila desired position of barrel 306 is achieved. When teeth of coil 314 orcoil 316 have a certain polarity, it is seen that barrel 306 will have acertain position relative to barrel 304 such that permanent magnetsthereof are aligned with teeth of coil 314 or coil 316. Thus, using thelens moving system of FIG. 8, precise positioning of lens elements canbe achieved. The motor described with reference to FIG. 9 is referred toas a hollow stepper motor since discrete stepwise positions of barrel306 relative to barrel 304 can be achieved wherein permanent magnets ofthe barrel are aligned with coil teeth having a certain polarity.Accordingly, with one of one or more hollow stepper motors, a lenssetting of imaging lens assembly 40 can be a lens setting correspondingto certain positions of imaging lens assembly lens elements.

Still referring to the lens moving assembly of FIG. 8 and the specificexemplary imaging lens assembly 40 shown in FIGS. 1, 2, and 3, a firstgroup of lens elements 420 can be disposed in first lens barrel 306 anda second group of lens elements 430 can be disposed in second lensbarrel 308. By application of movement controlling control signals tofirst coil set 310 and second coil set 312 contemporaneously, imaginglens assembly 40 can be moved relative to the image plane defined byimage sensor 32 without altering the relative positions of the lenselements of imaging lens assembly 40. Such movement is desirable in thecase where it is desired to change a best focus position of imaging lensassembly 40 without changing a focal length of imaging lens assembly 40.By application of movement controlling control signals to only one ofthe first or second coil sets at a given time, relative movement betweenfirst group 420 and second group 430 can be achieved. Such movement isdesirable in the case it is desired to change a best focus distance anda focal length of imaging lens assembly 40.

A major advantage of a hollow stepper motor configuration is reducedsize. The size of lens moving assembly 40 can be reduced furtherutilizing one or more of the further miniaturized configurations as aredescribed with reference to FIGS. 10-12.

In FIG. 10, there is described a non-zooming imaging lens assembly 40having an associated hollow stepper motor lens moving assembly. Innerbarrel 502 in the embodiment of FIG. 10 has a substantially uniformlydiametered support 506 for receiving lens elements 510, 511, 512. Asindicated in the view of FIG. 10, magnets 516 can be disposed at theouter surface of support 506. While the uniform diametered arrangementof support 506 might yield a reduction in manufacturing complexity andcosts, further miniaturization can be achieved with use of the design asshown in FIG. 11.

In the embodiment of FIG. 11, support 507 for receiving lens elements510, 511, 513 is not uniformly diametered; but rather, includes a widerdiametered region 520 and a smaller diametered region 522. Where imaginglens assembly 40 includes an aperture 525, the multiple diameteredsupport 507 can be provided without any change in the performance ofimaging lens assembly 40 by providing aperture 525 in the narrowdiametered region 522 of support 520 as shown in FIG. 11. With furtherreference to the embodiment of FIG. 11, threads 530 can be disposed atthe outer surface of the wider diametered region 520 of support 507,lens elements 510, 511 can be disposed in wider diametered region 520and lens element 513 can be disposed in narrow diametered region 522.

With still further reference to the embodiment of FIG. 11 having amultiple diametered support 507, magnets 517 can be disposed at theouter surface of support 507 in the narrow diameter region of support507 including lens aperture 525. Comparing FIGS. 10 and 11, it is seenthat while the embodiment of FIG. 10 and FIG. 11 include identicaloptical characteristics, the embodiment of FIG. 11 can be of reduceddiameter. Specifically, where magnets 517 are disposed about support 507at narrow diameter region 522, wherein aperture 525 is defined, themaximum diameter of inner barrel 503 (equal to the support outerdiameter plus 2× the thickness of the magnets) about aperture 525 isreduced relative to the maximum inner barrel diameter about aperture 525in the embodiment as shown in FIG. 10.

Another embodiment of a hollow stepper motor that can be used in a barcode reading terminal is shown in FIG. 12. In the embodiment of FIG. 12showing a zoom imaging lens assembly having first group 540, 541, 542and a second group 546, 547, 548 of lens elements, a first group of lenselements 540, 541, 542 is disposed in first inner barrel 550 and asecond group of lenses 546, 547, 548 is disposed in second inner barrel552. Each of first and second barrels 550, 552 in the embodiment of FIG.12 have multiple diameter supports 551, 553, respectively as describedin connection with the embodiment of FIG. 11. Further regarding theembodiment of FIG. 12, first inner barrel 550 and second inner barrel552 can be driven by electromagnetic energy radiating from shared coil560 disposed on outer barrel 566. With respect to first inner barrel550, shared coil 560 can perform a function as provided by coil 316 asdescribed relative to the embodiment of FIG. 8. With respect to secondinner barrel 308, shared coil 560 can perform a function as provided bycoil 318 as described in the embodiment of FIG. 8. By combining afunction of a plurality of coils into a single shared coil 560, a sizeof hollow stepper motor lens moving assembly 568 is reduced. Also, witha reduction of a coil, a control input is eliminated simplifying controlof the hollow stepper motor lens moving assembly 568. The embodiment ofFIG. 12 can be regarded as a lens moving assembly having first andsecond hollow stepper motors 569, 570 wherein the hollow stepper motorsshare a common coil.

In another aspect, a system of camming surfaces can be formedcomplementarily on inner barrels 550, 552 and outer barrel 566,respectively. In one embodiment, camming surfaces 750, 752 can be formedon an outer surface of inner barrels 550, 552, and complementary cammingsurfaces 762, 764 can be formed on an inner surface of outer barrel 566.Such camming surfaces can be provided so that barrels 550, 552 move adesired distance in a direction co-extensive with imaging axis 30 when abarrel 550, 552 is rotated about axis 30. Camming surfaces between abarrel 550, 552 and outer barrel 566 can be irregular so that a firsttime a barrel, e.g., barrel 550 is rotated an angle, α degrees, aboutaxis 30, the barrel moves x mm along axis 30 and further so that asecond time barrel 550 is moved α degrees about axis 30, the barrelmoves y mm along axis 30, x≠y. In one embodiment a camming surface of aninner barrel 550, 552 comprise a camming pin and a camming surface ofouter barrel 566 comprises a camming groove.

Terminal components illustrated in FIG. 4 can be disposed within andsupported by a hand held housing. An exemplary hand held housing 11 forincorporating and supporting terminal components is shown and describedin FIG. 13 and FIG. 14. As seen in FIG. 14, a plurality of circuitboards 402 can be supported by housing 11 by way of struts 404 extendingfrom interior walls of housing 11. An imaging module 300 which comprisesa lens moving assembly 302 having imaging axis 30 and image sensor 32can be disposed within housing 11 and can be supported by housing 11 byway of support 406 extending from an interior wall of housing 11.

Further aspects of terminal 10 are now described. Terminal 10 can beadapted so that when a trigger signal represented by timeline 202 (FIG.7) is active terminal 10 continually subjects newly captured frames ofimage data to decoding attempts until decoding is successful. Terminal10 can be adapted so that when terminal 10 successfully decodes anencoded message from a frame of image data (at time 280 shown in thetiming diagram of FIG. 7), terminal 10 automatically deactivates triggersignal represented by timeline 202, stops the application of exposurecontrol pulses to image sensor array 33, stops the application ofreadout control signals to image sensor array 33 and stops subjectingnewly captured frames of image data to decode attempts. Where terminal10 is a presentation reader, terminal 10 may be adapted to continuallycapture frames and subject such frames to a decode attempt after a firstmessage is decoded. In addition to the above, terminal 10 aftersuccessfully decoding a message by processing a frame of image data cansend a signal to an acoustic output device 99 to emit a good read beep,and can output a decoded message (e.g., by writing the decoded messageto a specified memory address designated for retaining decoded messages,by writing the decoded message to display 97 and/or by sending thedecoded message to an external computer). It has been mentioned thattrigger signal represented by timeline 202 can be deactivated when thereis a successful decode of a frame of image data. Terminal 10 can also beadapted so that trigger signal represented by timeline 202 isdeactivated when a user releases a trigger button 95.

Terminal 10 after trigger signal represented by timeline 202 is madeactive may subject several frames of image data to unsuccessful decodeattempts before successfully decoding a message from a frame of imagedata. In the specific example of FIG. 7, terminal 10 after triggersignal represented by timeline 202 is made active makes N−1 unsuccessfuldecode attempts by processing of frames 1 through N−1, until terminal 10successfully decodes an encoded message by processing of frame N (theframe having image data representing light incident on pixel arraypixels during exposure period EXP_(N)). It is understood that under onedifferent illumination or decodable indicia quality condition, terminal10 might successfully decode a first frame of image data subject to adecode attempt without unsuccessfully decoding any frames of image data.Under another different illumination or decodable indicia qualitycondition terminal 10 may successfully decode an Mth frame of image dataafter unsuccessfully decoding M−1 frames of image data, where M>>N.

Referring to the timing diagram of FIG. 7, a specific cycling patternfor cycling imaging lens assembly 40 between various lens settings isshown. In the specific example of FIG. 7, terminal 10 intermediate everysuccessive exposure period, changes a setting of imaging lens assembly40. In changing an imaging lens assembly setting where imaging lensassembly 40 includes multiple lens elements the changing of a lenssetting can include movement of one or more lens elements along imagingaxis 30. The lens setting cycling pattern shown in FIG. 7 has thecharacteristics of Configuration 1 as shown in Table A, below.

TABLE A Configuration Exposure Period and Lens Setting Coordination 1Exposure 1 2 3 4 5 6 7 8 9 10 11 12 . . . Period Lens a b c b a b c b ab c b . . . Setting 2 Exposure 1 2 3 4 5 6 7 8 9 10 11 12 . . . PeriodLens a b c a b c a b c a b c . . . Setting 3 Exposure 1 2 3 4 5 6 7 8 910 11 12 . . . Period Lens a a b b c c b b a a b b . . . Setting 4Exposure 1 2 3 4 5 6 7 8 9 10 11 12 . . . Period Lens a a a a a a a a aa a a . . . Setting 5 Exposure 1 2 3 4 5 6 7 8 9 10 11 12 . . . PeriodLens c c c c c c c c c c c c . . . Setting 6 Exposure 1 2 3 4 5 6 7 8 910 11 12 . . . Period Lens a  a′ b  b′ c  b′ b  a′ a  a′ b  b′ . . .Setting 7 Exposure 1 2 3 4 5 6 7 8 9 10 11 12 . . . Period Lens a a a ba a a b a a a b . . . Setting 8 Exposure 1 2 3 4 5 6 7 8 9 10 11 12 . .. Period Lens c c c b c c c b c c c b . . . Setting 9 Exposure 1 2 3 — —— — — — — — — Period Lens c c c c c c c c c c c c c Setting 10 Exposure1 2 3 4 5 6 7 8 9 10 11 12 13 Period Lens c c c c c c c c c c c c cSetting

Still referring to Table A, terminal 10 can have alternative exposureperiod and lens setting coordination characteristics. For example, inConfiguration 2, terminal 10 can be controlled so that a lens setting oflens 40 cycles back to setting (a) after reaching setting (c) instead ofreturning to setting (b) as indicated by Configuration 1. InConfiguration 1 and Configuration 2, terminal 10 establishes a new lenssetting for lens 40 intermediate every successive exposure period.However, as indicated by Configuration 3, terminal 10 can control lenssettings of imaging lens assembly 40 such that a lens setting of imaginglens assembly 40 remains at a constant setting for more than onesuccessive exposure period (e.g., 2, 3, 5, N) successive exposureperiods before a lens setting is changed. As indicated by Configurations4 and 5, terminal 10 can be controlled so that terminal 10 maintains asetting of imaging lens assembly 40 at a constant setting and does notchange a lens setting unless a different configuration is made active.In Configuration 4, terminal 10 is particularly well adapted to readdecodable indicia at close range. In Configuration 5, terminal 10 isparticularly well adapted to decode indicia at long range.

Imaging lens assembly 40 can have less than or more than three settings.As indicated by Configuration 6, imaging lens assembly 40 can have asetting (a′) intermediate of setting (a) and (b), and a setting (b′)intermediate of setting (b), and setting (b) and the additional settings(a′) and (b′) can be included in the cycle of settings.

A set of three subsequent exposure periods are referred to herein as acertain exposure period, a subsequent exposure period, and a furthersubsequent time period. For example, referring to the timing diagram ofFIG. 7 and Table A, exposure periods EXP₁, EXP₂, EXP₃ are in “certainframe,” “subsequent frame,” and “further subsequent frame” relation.Exposure periods EXP₃, EXP₄, EXP₅ are also in “certain,” “subsequent,”and “further subsequent” relation as well as the exposure periods EXP₁,EXP₄, EXP₅ and the exposure periods EXP₃, EXP₅, EXP_(N), etc. Theconvention employing the terms “certain,” “subsequent,” and “furthersubsequent” as described is also used to designate subsequent capturedframes and subsequent decoding periods herein.

As is shown in FIG. 13, terminal 10 can be adapted so that theConfigurations of Table A and other configurations are user selectable.For example, in one embodiment a user interface of terminal 10 caninclude the presented menu as shown in FIG. 13 wherein terminal 10displays buttons 802, 804, 806, 808 corresponding to each configurationoption as shown in Table 1. Buttons for the remaining configurations canbe accessed by actuating “more” button 810. When a user selects aparticular button, terminal 10 is adapted to operate in accordance withthe particular configuration selected until an operator selects anotherconfiguration.

In another embodiment, terminal 10 can be adapted to automatically cyclebetween one or more configurations described in Table A in response tofailed decode attempts. For example, terminal 10 can be adapted so thatafter trigger signal represented by timeline 202 is made active andterminal 10 encounters X consecutive decode failures, (consecutiveframes being subjected to a decode attempt without success) terminal 10may automatically switch to another configuration without trigger signalrepresented by timeline 202 being deactivated. In another embodiment,terminal 10 can be adapted so that terminal 10 automatically cyclesbetween Configurations of Table A between successive activations oftrigger signal represented by timeline 202. For example, terminal 10 canbe adapted so that when trigger signal 202 is initiated a first time,Configuration 1 is active and when initiated a second time after saidfirst time, another configuration e.g., Configuration 2 is active.

In still another embodiment, terminal 10 can be adapted so that theimaging lens assembly cycling configuration is responsive to a sensedcondition other than the sensed condition mentioned above, wherein thementioned sensed condition is an inability to decode a decodable indicia(indicated by consecutive frames being subjected to a decode attemptwithout success consecutive decode failures). A sensed condition can bee.g., a sensed terminal to target distance in one example. In oneembodiment, terminal 10 can be adapted to project a spot of light onto atarget substrate 50 carrying a bar code symbol 52 (bar code). Forexample, terminal 10 can be adapted so that aiming light source 610projects spot 611 onto target substrate 50. In such an embodiment, theterminal to target distance can be determined based on the location ofthe spot in a captured frame of image data provided the spot isprojected at a known angle from terminal 10. In one example, terminal 10may automatically activate Configuration 7 when a short range terminalto target distance is detected and can automatically activateConfiguration 8 when a long range terminal to target distance isdetected. In accordance with Configuration 7, terminal 10 primarilyestablishes the setting of imaging lens assembly 40 at setting (a) butoccasionally establishes the lens setting at setting (b). In accordancewith Configuration 8, terminal 10 primarily establishes the setting ofimaging lens assembly 40 at setting (c) but occasionally moves thesetting to setting (b) during a decode attempt. Terminal 10 can beadapted so that if terminal 10 is moved a distance away from a targetduring a decode attempt while terminal 10 captures and attempts todecode a succession of frames of image data, terminal 10 mayautomatically change a configuration thereof from Configuration 7 toConfiguration 8 so that a lens setting cycling pattern changes during adecode attempt while a trigger signal remains active.

With further reference to the configurations of Table A, Configuration 9is an exemplary still image picture taking configuration. Terminal 10can be adapted so that in a still image picture taking configuration,terminal 10 may capture a limited number of frames, e.g., 1 to J framesresponsively to a trigger signal being made active. In the specificembodiment, terminal 10 captures three frames responsively to a triggersignal being made active in the still image picture takingconfiguration, and averages the frames for noise reduction, prior tooutputting a still image frame.

Configuration 10 illustrates an exemplary motion video collectionconfiguration. Terminal 10 can be adapted so that responsively to atrigger signal being made active in a motion video collectionconfiguration, terminal 10 captures a plurality of frames in succession,and formats the frames into a motion video file format for storage andlater viewing and/or into a live streaming video format for liveviewing.

It is seen with reference to Table A that when in a still image picturetaking configuration or in a motion video configuration, a lens settingof imaging lens assembly 40 is set to setting (c) wherein the imaginglens assembly has a long range focus. When operating in Configuration 9(still image picture taking) or Configuration 10 (motion video),terminal 10, in one embodiment, avoids subjecting captured frames ofimage data to decode attempts.

A small sample of the methods of an apparatus described herein are asfollows.

A1. A bar code reading terminal comprising:

an image sensor having a plurality of pixels;

a multiple setting imaging lens assembly having a plurality of lenselements, the multiple setting imaging lens assembly having a pluralityof lens settings;

a hand held housing, wherein said image sensor is disposed within saidhand held housing;

wherein said lens settings of said imaging lens assembly includes atleast first, second, and third lens settings;

wherein said terminal when said lens setting is at said first lenssetting has a first best focus distance and a first focal length;

wherein said terminal when said lens setting is at said second lenssetting has a second best focus distance different from said first bestfocus distance and a focal length unchanged relative to said first focallength;

wherein said terminal when said lens setting is at said third lenssetting has a third best focus distance different from either of saidfirst or second best focus distance and a focal length different fromsaid first focal length; and

wherein said terminal is adapted so that when a trigger signal isactive, said terminal automatically cycles a lens setting of saidmultiple setting imaging lens assembly between said first, second, andthird lens settings;

wherein said terminal is further adapted so that when a trigger signalis active, said terminal captures a certain subsequent and a furthersubsequent frame of image data, and subjects each of the certain,subsequent and further subsequent frames of image data to a decodeattempt, the first frame having image data representing light incidenton pixels of said image sensor when said imaging lens assembly is at afirst lens setting, the subsequent frame having image data representinglight incident on pixels of said image sensor when said imaging lensassembly is at said second lens setting, the further subsequent framehaving image data representing light incident on pixels of said imagesensor when said imaging lens assembly is at said third lens setting.

A2. The bar code reading terminal of claim A1, wherein said image sensoris a 1D image sensor.

A3. The bar code reading terminal of claim A1, wherein said image sensoris a 2D image sensor.

A4. The bar code reading terminal of claim A1, wherein said bar codereading terminal includes a hollow stepper motor for facilitating motionof at least one lens element of said imaging lens assembly.

A5. The bar code reading terminal of claim A1, wherein said terminal inan active reading state cycles between said first, second, and thirdlens settings such that during a certain frame exposure period, saidimaging lens assembly is set to said first lens setting, in a subsequentframe exposure period, said imaging lens assembly is set to a secondlens setting, and further so that in a further subsequent frame exposureperiod occurring after said subsequent time period said imaging lensassembly is set to a third lens setting.A6. The bar code reading terminal of claim A1, wherein said certain,subsequent, and further subsequent frames of image data are successivelycaptured frames of image data.A7. The bar code reading terminal of claim A1, wherein said terminal,has a plurality of groupings of lens elements, and wherein said terminalis adapted so that when cycling between said first and second lenssetting, said terminal maintains a spacing between said groups whilechanging a distance between said plurality of groupings and said imagesensor.B1. A bar code reading terminal comprising:

an image sensor having a plurality of pixels;

a multiple setting imaging lens assembly for focusing an image of targetbar code onto an active surface of said image sensor, the multiplesetting imaging lens assembly having a plurality of lens elements;

a hand held housing, wherein said image sensor is disposed within saidhand held housing;

at least one hollow stepper motor for moving at least one lens elementof said multiple setting imaging lens assembly; and

wherein said terminal is further adapted so that said terminal in anactive reading state subjects each of said first and subsequent framesof image data to a decode attempt for attempting to decode said targetbar code.

B2. The bar code reading terminal of claim B1 wherein said lens settingsof said imaging lens assembly include at least first, second, and thirdlens settings, wherein said terminal when said lens setting is at saidfirst lens setting has a first best focus distance and a first focallength, wherein said terminal when said lens setting is at said secondlens setting has a second best focus distance different from said firstbest focus distance and a focal length constant relative to said firstfocal length, wherein said terminal when said lens setting is at saidthird lens setting has a third best focus distance different from eitherof said first or second best focus distance and a focal length differentfrom said first focal length, and wherein said terminal is adapted sothat in an active reading state said terminal automatically cycles alens setting of said multiple setting imaging lens assembly between saidfirst, second, and third lens settings.B3. The bar code reading terminal of claim B1, wherein said subsequentexposure period is an exposure period succeeding said first exposureperiod.C1. A bar code reading terminal comprising:

an image sensor having a plurality of pixels;

a multiple setting imaging lens assembly for focusing an image of targetbar code onto an active surface of said image sensor, the multiplesetting imaging lens assembly having a plurality of lens elements, themultiple setting imaging lens assembly having a plurality of lenssettings;

a hand held housing, wherein said image sensor is disposed within saidhand held housing;

wherein said terminal is adapted so that responsively to a triggersignal of said terminal being made active, said terminal captures atleast a certain and subsequently a subsequent frame of image data, saidcertain frame of image data representing light incident on pixels ofsaid image sensor during a certain exposure period, said subsequentframe of image data representing light incident on pixels of said imagesensor during a subsequent exposure period occurring after said certainexposure period;

wherein said terminal is further adapted so that said imaging lensassembly has a first lens setting during said first exposure period anda second lens setting during said subsequent exposure period;

wherein said terminal is further adapted so that said terminal in anactive reading state subjects each of said certain and subsequent framesof image data to a decode attempt for attempting to decode said targetbar code, the terminal attempting to decode said certain frame of imagedata during a certain decoding period and attempting to decode saidsubsequent frame of image data during a subsequent decoding period;

wherein said imaging lens assembly is adapted so that said multiple lenssettings of said multiple setting imaging lens are facilitated bymovement of at least one lens element during a motion period of saidimaging lens assembly; and

wherein said terminal in an active reading state is adapted in suchmanner that at least one of said certain and subsequent decoding periodsis coincident with a motion period of said imaging lens assembly so thatsaid terminal in an active reading state moves at least one lens elementof said imaging lens assembly to achieve a different lens setting whilesimultaneously processing image data to attempt to decode said targetbar code.

C2. The bar code reading terminal of claim C1 wherein said lens settingsof said imaging lens assembly include at least first, second, and thirdlens settings, wherein said terminal when said lens setting is at saidfirst lens setting has a first best focus distance and a first focallength, wherein said terminal when said lens setting is at said secondlens setting has a second best focus distance different from said firstbest focus distance and a focal length unchanged relative to said firstfocal length, wherein said terminal when said lens setting is at saidthird lens setting has a third best focus distance different from eitherof said first or second best focus distance and a focal length differentfrom said first focal length, and wherein said terminal is adapted sothat in an active reading state said terminal automatically cycles alens setting of said multiple setting imaging lens assembly between saidfirst, second, and third lens settings.C3. The bar code reading terminal of claim C1, wherein said bar codereading terminal includes at least one hollow stepper motor for movingat least one lens element of said multiple setting imaging lensassembly.C4. The bar code reading terminal of claim C1, wherein said terminal isadapted so that further responding to a trigger signal being madeactive, said terminal captures a further subsequent frame of image data,said terminal further being adapted so that said terminal in an activeready state subjects ends of said certain, subsequent and furthersubsequent frames of image data to a decode attempt.D1. A bar code reading terminal comprising:

an image sensor comprising a plurality of pixels;

an imaging lens assembly comprising lens elements for focusing an imageonto an active surface of said image sensor;

a lens moving assembly for moving lens elements of said imaging lensassembly, wherein said lens moving assembly includes at least one innerbarrel and an outer barrel, the inner barrel including a support forsupporting at least some of said lens elements, the support having anarrower diameter section defining an aperture and a wider diametersection, the inner barrel having permanent magnets being driven byelectromagnetic energy radiating from at least one coil disposed at saidouter coil, wherein said magnets of said inner coil are disposed aboutsaid inner section of said support;

wherein said bar code reading terminal is adapted to capture,responsively to a trigger signal being made active, a plurality offrames of image data representing light incident on said plurality ofpixels; and

wherein said bar code reading terminal is further adapted so thatresponsively to trigger signal being made active said terminal subjectssaid plurality of frames to a decode process for decoding a bar codesymbol.

E1. A bar code reading terminal comprising:

an image sensor comprising a plurality of pixels;

an imaging lens assembly comprising lens elements for focusing an imageonto an active surface of said image sensor;

a lens moving assembly for moving lens elements of said imaging lensassembly, wherein said lens moving assembly includes an outer barrel, afirst inner barrel and a second inner barrel, wherein a first group oflens elements are disposed in said first inner barrel and a second groupof lenses are disposed in said second inner barrel, the first and secondinner barrels having magnets disposed about a circumference thereof, andwherein said outer barrel includes a common coil for radiatingelectromagnetic energy for simultaneously driving both of said firstinner barrel and said second inner barrel;

wherein said bar code reading terminal is adapted to capture,responsively to a trigger signal being made active, a plurality offrames of image data representing light incident on said plurality ofpixels; and

wherein said bar code reading terminal is further adapted so thatresponsively to trigger signal being made active said terminal subjectssaid plurality of frames to a decode process for decoding a bar codesymbol.

F1. A bar code reading terminal comprising:

an image sensor comprising a plurality of pixels;

an imaging lens assembly comprising lens elements for focusing an imageonto an active surface of said image sensor;

an imaging axis extending perpendicularly through said imaging lensassembly;

a lens moving assembly for moving lens elements of said imaging lensassembly, wherein said lens moving assembly includes an outer barrel andan inner barrel, wherein camming surfaces are disposed on said outerbarrel and said inner barrel, wherein permanent magnets are disposedabout said inner barrel, and wherein said outer barrel includes at leastone coil radiating electromagnetic energy for rotating said inner barrelabout said axis, the camming surfaces guiding moving in a directioncoextensive with said axis as said inner barrel is rotated about saidaxis;

wherein said bar code reading terminal is adapted to capture,responsively to a trigger signal being made active, a plurality offrames of image data representing light incident on said plurality ofpixels; and

wherein said bar code reading terminal is further adapted so thatresponsively to trigger signal being made active said terminal subjectssaid plurality of frames to a decode process for decoding a bar codesymbol.

F2. The bar code reading terminal of claim F1, wherein said cammingsurfaces are arranged so that a first time said inner barrel is rotateda certain number of radians about said axis, said inner barrel moves adistance of x mm aligning said axis and further so that a second timesaid inner barrel is rotated a certain number of degrees about saidaxis, said inner barrel moves a distance of y along said axis, wherex≠y.G1. A bar code reading terminal comprising:

an image sensor having a plurality of pixels;

a multiple setting imaging lens assembly having a plurality of lenselements, the multiple setting imaging lens assembly having a pluralityof lens settings,

a hand held housing, wherein said image sensor is disposed within saidhand held housing;

wherein said lens settings of said imaging lens assembly includes atleast first, second, and third lens settings;

wherein said terminal when said lens setting is at said first lenssetting has a first best focus distance and a first focal length;

wherein said terminal when said lens setting is at said second lenssetting has a second best focus distance different from said first bestfocus distance and a second focal length different relative to saidfirst focal length;

wherein said terminal when said lens setting is at said third lenssetting has a third best focus distance different from either of saidfirst or second best focus distance and a focal length different fromsaid first and said second focal length;

wherein said terminal is adapted so that when a trigger signal isactive, said terminal automatically cycles a lens setting of saidmultiple setting imaging lens assembly between said first, second, andthird lens settings; and

wherein said terminal is adapted further so that when a trigger signalis active, said terminal captures a certain, subsequent and a furthersubsequent frame of image data, and subjects each of the firstsubsequent and further subsequent frames of image data to a decodeattempt, the first frame having image data representing light incidenton pixels of said image sensor when said imaging lens assembly is atfirst lens setting, the subsequent frame having image data representinglight incident on pixels of said image sensor when said imaging lensassembly is at said second lens setting, the further subsequent framehaving image data representing light incident on pixels of said imagesensor when said imaging lens assembly is at said third lens setting.

G2. The bar code reading terminal of claim G1, wherein said image sensoris a 1D image sensor.

G3. The bar code reading terminal of claim G1, wherein said image sensoris a 2D image sensor.

G4. The bar code reading terminal of claim G1, wherein said bar codereading terminal includes a hollow stepper motor for facilitating motionof at least one lens element of said imaging lens assembly.

G5. The bar code reading terminal of claim G1, wherein said certain,subsequent, and further subsequent frames of image data are successivelycaptured frames of image data.

G6. The bar code reading terminal of claim G1, wherein said terminal,has a plurality of groupings of lens elements, and wherein said terminalis adapted so that when cycling between said first and second lenssetting, said terminal maintains a spacing between said groups whilechanging a distance between said plurality of groupings and said imagesensor.H1. A bar code reading terminal comprising:

an image sensor having a plurality of pixels;

a multiple setting imaging lens assembly having a plurality of lenssettings;

a hand held housing, wherein said image sensor is disposed with saidhand held housing;

wherein said bar code reading terminal is capable of operating accordingto a first configuration and a second configuration, wherein saidterminal when said first configuration is active cycles between at leastsome of said plurality of lens settings when capturing frames of imagedata responsively to a trigger signal being made active;

wherein said terminal when said second configuration maintains a settingof said multiple setting lens assembly at a single setting whencapturing at least one frame of image data responsively to a trigger,wherein said first configuration is a configuration in which saidterminal is optimized for reading bar code symbols; and

wherein said second configuration is a configuration optimizing saidterminal for one of still image picture taking or motion videocollection, wherein said terminal has a user interface enabling operatorselection of said first configuration and said second configuration.

I1. A bar code reading terminal comprising:

an image sensor having a plurality of pixels;

a multiple setting imaging lens assembly having a plurality of lenssettings;

a hand held housing, wherein said image sensor is disposed within saidhand held housing;

wherein said bar code reading terminal is capable of operating accordingto a first configuration and a second configuration;

wherein said terminal when said first configuration is active cyclesbetween at least some of said plurality of lens settings according to afirst cycling pattern when capturing frames of image data;

wherein said terminal when said second configuration is active cyclesbetween at least some of said plurality of lens settings according to asecond cycling pattern when capturing frames of image data;

wherein said terminal when said first configuration is active isoptimizing for reading bar code symbols at a relatively shorter range;and

wherein said terminal when said second configuration is active isoptimized for reading bar code symbols at a relatively longer readingrange.

I2. The bar code reading terminal of claim I1, wherein said terminal hasa user interface enabling an operator to select between said first andsecond configurations.

I3. The bar code reading terminal of claim I1, wherein said terminal isadapted so that said terminal can switch between said first and secondconfigurations responsively to a sensed condition while a trigger signalremains active.

I4. The bar code reading terminal of claim I1, wherein said terminal isadapted so that said terminal can switch between said first and secondconfigurations responsively to a sensed condition while a trigger signalremains active, the sensed condition being a sensed distance of saidterminal to a target.I5. The bar code reading terminal of claim I1, wherein said terminal isadapted so that said terminal can switch between said first and secondconfigurations responsively to a sensed condition while a trigger signalremains active, the sensed condition being an inability to decode anindicia.J1. A bar code reading terminal comprising:

an image sensor having a plurality of pixels;

a multiple setting imaging lens assembly having a plurality of lenssettings;

a hand held housing, wherein said image sensor is disposed within saidhand held housing;

wherein said bar code reading terminal is capable of operating accordingto a first configuration and a second configuration;

wherein said terminal when said first configuration is active cyclesbetween at least some of said plurality of lens settings according to afirst cycling pattern when capturing frames of image data;

wherein said terminal when said second configuration is active maintainsa setting of said multiple setting lens assembly at a fixed lens settingwhen capturing frames of image data; and

wherein said terminal is adapted so that said terminal can switch fromone said first configuration and said second configuration to the otherof said first and second configurations responsively to a sensedcondition that is sensed while a trigger signal is active.

J2. The terminal of claim J1, wherein said sensed condition is adistance from said terminal to a target.

J3. The terminal of claim J1, wherein said sensed condition is aninability to decode an indicia.

K1. A bar code reading terminal comprising:

an image sensor having a plurality of pixels;

a multiple setting imaging lens assembly having a plurality of lenssettings;

a hand held housing, wherein said image sensor is disposed within saidhand held housing;

wherein said bar code reading terminal is capable of operating accordingto a first configuration and a second configuration;

wherein said terminal when said first configuration is active cyclesbetween at least some of said plurality of lens settings according to afirst cycling pattern when capturing frames of image data;

wherein said terminal when said second configuration is active cyclesbetween at least some of said plurality of lens settings according to asecond cycling pattern when capturing frames of image data, the secondcycling pattern being different from said first cycling pattern; and

wherein said terminal is adapted so that said terminal can switch fromone said first configuration and said second configuration to the otherof said first and second configurations responsively to a sensedcondition that is sensed while a trigger signal is active.

K2. The terminal of claim K1, wherein said sensed condition is adistance from said terminal to a target.

K3. The terminal of claim K1, wherein said sensed condition is aninability to decode an indicia.

K4. The terminal of claim K1, wherein said multiple setting imaging lensassembly comprises a plurality of lens elements.

K5. The terminal of claim K1, wherein said multiple setting imaging lensassembly includes moving lens elements.

K6. The terminal of claim K1, wherein said multiple setting imaging lensassembly includes moving lens elements, and wherein movement of saidmoving lens elements is provided by a hollow stepper motor.

While the present invention has been particularly shown and describedwith reference to certain exemplary embodiments, it will be understoodby one skilled in the art that various changes in detail may be effectedtherein without departing from the spirit and scope of the invention asdefined by claims that can be supported by the written description anddrawings. Further, where exemplary embodiments are described withreference to a certain number of elements it will be understood that theexemplary embodiments can be practiced utilizing less than the certainnumber of elements.

1. A bar code reading terminal comprising: an image sensor having aplurality of pixels; a multiple setting imaging lens assembly forfocusing an image of target bar code onto an active surface of saidimage sensor, the multiple setting imaging lens assembly having aplurality of lens elements; a hand held housing, wherein said imagesensor is disposed within said hand held housing; at least one hollowstepper motor for moving at least one lens element of said multiplesetting imaging lens assembly; and wherein said terminal is furtheradapted so that said terminal in an active reading state subjects eachof a first and subsequent frame of image data to a decode attempt forattempting to decode said target bar code; wherein said imaging lensassembly includes at least first, second, and third lens settings,wherein said terminal when said lens setting is at said first lenssetting has a first best focus distance and a first focal length,wherein said terminal when said lens setting is at said second lenssetting has a second best focus distance different from said first bestfocus distance and a focal length constant relative to said first focallength, wherein said terminal when said lens setting is at said thirdlens setting has a third best focus distance different from either ofsaid first or second best focus distance and a focal length differentfrom said first focal length, and wherein said terminal is adapted sothat in an active reading state said terminal automatically cycles alens setting of said multiple setting imaging lens assembly between saidfirst, second, and third lens settings.
 2. The bar code reading terminalof claim 1, wherein an exposure period in which the subsequent frame ofimage data is exposed is an exposure period succeeding an exposureperiod in which the first frame of image data is exposed.
 3. The barcode reading terminal of claim 1, wherein the subsequent frame of imagedata succeeds the first frame of image data.
 4. The bar code readingterminal of claim 1, wherein said multiple setting imaging lens assemblyincludes moving lens elements.
 5. The bar code reading terminal of claim1, wherein said multiple setting imaging lens assembly includes movinglens elements.
 6. The bar code reading terminal of claim 1, wherein saidmultiple setting imaging lens assembly includes moving lens elements,and wherein movement of said moving lens elements is provided by amotor.
 7. The bar code reading terminal of claim 1, wherein saidmultiple setting imaging lens assembly includes moving lens elements,and wherein movement of said moving lens elements is provided by ahollow stepping motor.
 8. A bar code reading terminal comprising: animage sensor comprising a plurality of pixels; an imaging lens assemblycomprising lens elements for focusing an image onto an active surface ofsaid image sensor; an imaging axis extending perpendicularly throughsaid imaging lens assembly; a lens moving assembly for moving lenselements of said imaging lens assembly, wherein said lens movingassembly includes an outer barrel and an inner barrel, wherein cammingsurfaces are disposed on said outer barrel and said inner barrel,wherein permanent magnets are disposed about said inner barrel, andwherein said outer barrel includes at least one coil radiatingelectromagnetic energy for rotating said inner barrel about said axis,the camming surfaces guiding moving in a direction coextensive with saidaxis as said inner barrel is rotated about said axis; wherein said barcode reading terminal is adapted to capture, responsively to a triggersignal being made active, a plurality of frames of image datarepresenting light incident on said plurality of pixels; and whereinsaid bar code reading terminal is further adapted so that responsivelyto trigger signal being made active said terminal subjects saidplurality of frames to a decode process for decoding a bar code symbol.9. The bar code reading terminal of claim 8, wherein said cammingsurfaces are arranged so that a first time said inner barrel is rotateda certain number of radians about said axis, said inner barrel moves adistance of x mm aligning said axis and further so that a second timesaid inner barrel is rotated a certain number of degrees about saidaxis, said inner barrel moves a distance of y along said axis, wherex≠y.
 10. The bar code reading terminal of claim 8, wherein said bar codereading terminal includes a hand held housing in which the image sensoris disposed.
 11. A bar code reading terminal comprising: an image sensorhaving a plurality of pixels; a multiple setting imaging lens assemblyhaving a plurality of lens settings; a hand held housing, wherein saidimage sensor is disposed within said hand held housing; wherein said barcode reading terminal is operative according to a first configurationand a second configuration; wherein said terminal when said firstconfiguration is active cycles between at least some of said pluralityof lens settings according to a first cycling pattern when capturingframes of image data; wherein said terminal when said secondconfiguration is active cycles between at least some of said pluralityof lens settings according to a second cycling pattern when capturingframes of image data; wherein said terminal when said firstconfiguration is active optimized for reading bar code symbols at arelatively shorter range; and wherein said terminal when said secondconfiguration is active is optimized for reading bar code symbols at arelatively longer reading range.
 12. The bar code reading terminal ofclaim 11, wherein said terminal has a user interface enabling anoperator to select between said first and second configurations.
 13. Thebar code reading terminal of claim 11, wherein said terminal is adaptedso that said terminal can switch between said first and secondconfigurations responsively to a sensed condition while a trigger signalremains active.
 14. The bar code reading terminal of claim 11, whereinsaid terminal is adapted so that said terminal can switch between saidfirst and second configurations responsively to a sensed condition whilea trigger signal remains active, the sensed condition being a senseddistance of said terminal to a target.
 15. The bar code reading terminalof claim 11, wherein said terminal is adapted so that said terminal canswitch between said first and second configurations responsively to asensed condition while a trigger signal remains active, the sensedcondition being an inability to decode an indicia.
 16. The bar codereading terminal of claim 11, wherein said multiple setting imaging lensassembly includes moving lens elements, and wherein movement of saidmoving lens elements is provided by a motor.
 17. The bar code readingterminal of claim 11, wherein said multiple setting imaging lensassembly includes moving lens elements, and wherein movement of saidmoving lens elements is provided by a hollow stepping motor.
 18. The barcode reading terminal of claim 17, wherein the bar code reading terminalincludes a trigger button, and wherein the bar code reading terminal isconfigured so that the trigger signal is made active by depression of atrigger button.
 19. The bar code reading terminal of claim 18, whereinthe bar code reading terminal is operative to capture a plurality offrames of image data responsively to activation of a trigger signal. 20.The bar code reading terminal of claim 11, wherein said terminal isadapted so that said terminal can switch between said first and secondconfigurations responsively to a sensed condition.